1. Field of the Invention
The present invention relates to a sensory structure of touch panel, and more particularly to a sensory structure of capacitive touch panel and a capacitive touch panel having the same.
2. Description of the Related Art
Touch sensing technology is broadly applied in the present electronic application for data input. In this case, the information is read out or transmitted while the user touches the screen with the finger or the stylus, so that the buttons, keyboards or joysticks, which are desired for the conventional electronic apparatus, could be omitted.
Depending on the principles adopted for sensing, the touch panels are grouped into such as resistive touch panels, capacitive touch panels, infrared (IR) touch panels and ultrasonic wave ones. Regarding the IR touch panels and the ultrasonic wave ones, an IR or ultrasonic wave transmitting unit is arranged on one side of the respective X-direction and Y-direction of the screen, and on the other side thereof a receiving unit is configured. The movement of IR-ray or ultrasonic wave would be changed while the screen is touched by the user, and the touch position is accordingly measured and determined for data input. With respect to the resistive touch panel, which is fabricated by the lamination of an upper and a lower indium tin oxide (ITO) conductive films, the voltage variation thereof is generated while the upper and the lower electrodes of ITO are conducted through the touch pressure, and is detected by a controller, so that the touch position for data input is determined. The capacitive touch panel is constructed by the transparent glass substrate with a layer of metal oxide coated thereon, where a uniformly distributed electrical field is produced throughout the surface of the substrate by the application of voltage from the four corners thereof. By detecting the capacitance variation caused by static-electric reaction between the user's finger and the electric field, the touch position for data input is determined.
The capacitive touch panel is advantageous in the design of dust-preventing, anti-fire, anti-scratch and high resolution. Nevertheless, an erroneous determination may occur in case of being exposed to electrostatic or humid environment since the sensory structure of the capacitive touch panel is easily affected thereby. Accordingly, it is relatively more difficult to design the structure and circuitry of the sensory structure to further increase the sensitivity of the capacitive touch panel, and hence the fabrication cost thereof may be so significant.
The sensory electrode of a conventional capacitive touch panel is a sensory matrix of plural sensory structures, wherein each of the sensory structure is usually an ITO unit designed in regular shapes (such as diamond), and it is electrically connected by a single trace between units. In this case, a broken circuit could easily occur due to the problem of trace breaking the electric connection of the sensory structure. Moreover, since the conventional sensory matrix is composed of plural panel sensory structures, besides the use of additional electrode material, the performance of touch panel is also affected by the decreasing of transparency thereof.
Furthermore, because the thickness of touch panel is required thinner, the thickness of cover lens thereof may be reduced so that the wiring or pattern located under the cover lens will become visible, affecting the appearance of the device adopting such touch panel.
For overcoming the mentioned issues, the present invention provides a sensory structure of capacitive touch panel and capacitive touch panel having the same. The novel design of sensory structure accompanied with double trace bridge connection could avoid the broken circuit from single trace failure therein, reduce the use of ITO to decrease the resistance of touch panel, and increase the transparency thereof.